Non-corrosive lubricating compositions



- 3,039,961 NON-CORROSIVE LUBRICATING COMPOSITIONS Robert J. Harker,Terre Haute, Ind, assignor to Commercial Solvents Corporation, New York,N.Y., a corporation of Maryland No Drawing. Filed May 8, 1959, Ser. No.811,802 Claims. ((31. 252-475) My invention relates to non-corrosivelubricating compositions. More particularly, it relates to non-corrosivelubricating compositions comprising a mercapto oxazoline having thefollowing structural formula R2 R. H l 6 C where R is a member selectedfrom the group consisting of CH QH Ol-l, and C H and R is a memberselected from the group consisting of CH OH, CH and H.

It is well known to the art that substantially all hydrocarbonlubricating oils are susceptible to harmful oxidation. The degree ofsusceptibility depends on the process used for refinement and the degreeto which readily oxidizable substances are removed. A satisfactoryrefined lubricating oil can be obtained by refining a crude hydrocarbonoil in the presence of sulfuric acid and treating the refined oil withvarious compositions; among them silica gel, natural clay, activatedcharcoal and A101 Such a lubricating oil, however, tends to form acidicsubstances when subjected to oxidizing conditions. These acidicsubstances are undesirable and have a corrosive effect upon the metalswith which the lubricating oil comes in contact during lubrication. Thisfactor not only shortens the useful life of the lubricating composition,but causes the deterioration of much expensive machinery.

Generally, a suitable noncorrosive lubricating composition minimizes thecorrosive etfect of oxidation products upon the metals with which alubricant comes in contact during lubrication and forms a continuousfilm upon metal surfaces which will resist breakage over extendedperiods of time even though continuously exposed to the oxidationproducts normally formed in a lubricating oil.

I have now discovered that a highly satisfactory noncorrosive lubricantwhich will form a protective film on metal surfaces, said film beingresistant to breakage by oxidation products over an extended period oftime, can be prepared by adding a mercapto oxazo-line having thefollowing structural formula where R is a member selected from the groupconsisting of CH CH OH, and C l-I and R is a member selected from thegroup consisting of CH CH OH, and H, to a lubricating oil. Examples ofthe above-described mercapto oxazolines which are operative in myinvention are Z-mercapto 4 hydroxymethylt-methyl 2 oxazoline, 2 mercapto4,4 dimethyl 2 oxazoline, Z-mercapto- 4,4 dihydroxymethyl 2 oxazoline,2-mercapto-4- 3,039,61 Patented June 19, 1962 ethyl 2 oxazoline,Z-mercapto-4-ethyl-4-hydroxymethyl- 2-oxazoline, etc.

In accordance with my invention, the mercapto oxazolines can be added tothe desired lubricant in amounts of from about 0.2 to 10% by weight ofthe lubricating oil. However, I prefer to use from about 0.5 to 2% byweight of the mercapto oxazolines.

The corrosiveness of the lubricant can be tested by means of variousdevices. One of these devices is the Underwood oxidation test apparatus.

The Underwood oxidation test apparatus comprises essential-ly an oilsump containing an electric heater, a gear pump driven by a Ahorsepowerelectric motor, a tube containing four orifices, a connectingmeans connecting the oil sump. and the tube, a 30 mesh wire screenpositioned between the orifices and the oil sump, and a rectangular boxcontaining all of the aforementioned, except the connecting means andthe gear pump. The apparatus is fitted with several control attachments,such as an adjustable thermostatic control attached'to a thermocouplefor maintaining the desired temperature of the oil, a pressure gauge, aby-pass valve for adjustment to the desired pressure and a controlswitch for the electric immersion heaters.

The Underwood oxidation test is conducted by charging the desired amountof the test oil containing a suitable oxidation accelerator into theapparatus, placing two copper-lead bearings backed with a copper stripin position opposite the orifices, starting the pump and regulating thetemperature and pressure. The test can be conducted for any prescribedlength of time after which the bearings are cleaned and weighed. Bycalculating the loss in weight of the bearings the amount of corrosionproduced by a lubricating composition containing an oxidationaccelerator can be compared to the amount of corrosion produced by alubricating composition tested under the same conditions containing anoxidation accelerator and a corrosion inhibitor.

The oil base which can be used to prepare the noncorrosive lubricatingcomposition of my invention is preferably a hydrocarbon lubricating oilwhich will not readily decompose over extended periods of time. Thehydrocarbon oil used in preparing the non-corrosive lubricants of myinvention can also contain constituents to improve the pour point, etc.Materials used in the art for these purposes which are compatible withthe hydrocarbon oil will be found to be useful in the non-corrosivelubricant of my invention.

The following examples are set. out to illustrate my invention. It isnot intended that the invention be limited to the materials, proceduresand proportions set out therein. Various equivalents of my inventionwill obviously occur to those skilled in the art and I intend to includesuch equivalents within the scope of my invention.

Example I 2,500 mls. lOf test lubricant containing Kendall SAE No. 10oil and 0.01% by weight Fe O as iron naphthenate was charged to theUnderwood oxidation apparatus. Two previously weighed copper-leadbearing balls were fixed in position opposite the orifices. The heaterswere turned to a temperature of 325 F. and the pressure was regulated to10 p.s.i. The test was continued for 10 hours, after which the ballswere cleaned by a special solvent consisting of equal parts of denaturedalcohol, toluene and ethyl acetate and weighed to determine the weightloss due to corrosion. The table below shows the results of the test andshows the amount of corrosion produced by the lubricating compositioncontaining an I oxidation accelerator.

Test 1 Test 2 Weight before test/gins 41. 9021 41. 9520 Weight altertest/gms -u 41. 7585 41. 0063 Weight loss 0. 1436 0. 1457 Percent weightloss I 0. 342 0. 347

Example I] 2,500 mls. of test lubricant containing Kendall SAE No. 10oil,'0.0l% Fe o as iron naphthenate by weight and 1% by weight2-mercapto-4-hydroxymethyl-4-methyl- 2-oxazoline was charged to theUnderwood apparatus, The Underwood oxidation test was performed asdescribed in Example I. The table below shows the results of the testand shows the amount of corrosion produced by a lubricating compositioncontaining an oxidation accelerator and a corrosion inhibitor.

Now having described my invention, What I claim is: l. A lubricatingcomposition consisting essentially of a hydrocarbon lubricating oil andfrom about 0.2% to 10% by weight on the weight of the hydrocarbon lubri-4 eating oil of a mercapto oxazoline having the following generalformula where R is a member selected from the group consisting of CH CHOH and C H and R is a member selected from the group consisting of CH CHOH and H.

2. The lubricating composition of claim 1 wherein the mercapto oxazolineis present in amounts of from about 0.5% to about 2% by weight.

3. The lubricating composition of claim 1 wherein the mercapto oxazolineis 2-mercapto-4-hydroxyl-4 methyl-2- oxazoline.

4. The lubricating composition of claim 1 wherein the mercapto oxazolineis 2 mercapto 4,4 dimethyl-Z- oxazoline.

5. The lubricating composition of claim 1 wherein the mercapto oxazolineis 2-mercapto-4,4-dihydroxymethyl- 2-oxazoline.

References Cited in the file of this patent UNITED STATES PATENTS2,206,152 Bennett July 2, 1940 2,348,917 Mathes May 16, 1944 2,364,399Williams et al. Dec. 5, 1944 2,776,977 DAmico Jan. 8, 1957 2,860,962Bluestone Nov. 18, 1958 2,953,573 Bluestone Sept. 20, 1960

1. A LUBRICATING COMPOSITION CONSISTING ESSENTIALLY OF A HYDROCARBONLUBRICATING OIL AND FROM ABOUT 0.2% TO 10% BY WEIGHT ON THE WEIGTH OFTHE HYDROCARBON LUBRICATING OIL OF A MERCAPTO OXAZOLINE HAVING THEFOLLOWING GENERAL FORMULA